diagnostictesting

YOU MUST BE EATING GLUTEN FOR BLOOD AND BIOPSY TESTING TO BE ACCURATE!!!

RESULTS: Twenty
patients could be followed during GFD and all antibody titres fell
sharply within 1 month after introduction of a GFD and continued to
decline during the survey interval. Thirty days after beginning the diet
only 58, 84, 74 and 53% of all patients had positive antibody levels of
tTGrh, tTGgp, EmA and AGA respectively.

Are you scheduled for a biopsy? Are you eating gluten? Any changes in your diet can affect the accuracy of your biopsy results. It is necessary for you to be eating gluten every day for at least 4-8 weeks before the procedure. If you are scheduled for a biopsy and are not eating gluten, talk to your doctor about what is necessary to obtain accurate results. If you have a biopsy and have eaten gluten only a short time before the test, you and your physician will not know if a negative test result is accurate or due to your diet.

If you are symptomatic and/or have tested positive to any of the antibody tests but failed to show biopsy damage, insist on periodic retesting. It is not uncommon for someone to have a negative biopsy one year, but a positive biopsy a couple of years later. It is also not uncommon to have negative blood tests for several years, which turn positive at a later date. And of course, even with a negative celiac biopsy, gluten sensitivity may be the cause of your symptoms. Read on!

A complete gluten sensitivity /celiac panel includes the following blood tests:

A newer test, anti-deamidated gliadin,
has been developed over the last several years and some labs are
beginning to automatically substitute it instead of the original
antigliadin antibody tests. The newer test is more specific to "celiac
disease / villous atrophy", which is not helpful when looking for gluten
sensitivity manifesting in non-gut ways (like neurological disease or
other autoimmune disease), or when there are gut symptoms that have not yet caused villous atrophy. BE SURE your doctor orders the original
antigliadin tests. DOUBLE CHECK that the right tests are ordered, and
DOUBLE CHECK that the right tests were run. You
want anti-gliadin IgA and anti-gliadin IgG, over anti-deamidated
gliadin.... or all of them!

To save cost, the celiac panel
is often reduced to a single test... the anti-tTG IgA. Insist on more
thorough testing than this single screening test!

Total serum IgA should
always be run to rule out a condition called IgA deficiency. The other IgA
tests are not reliable measures in someone who does not make enough
IgA.

Many "experts" consider
the original antigliadin test as optional and outdated. It is
said that antigliadin antibodies are not specific to celiac disease,
but they are often the first to show and are of increased
significance for those who may have gluten sensitivity manifesting as
neurological disease. You want it!

The anti-endomysial antibody test is very specific for villous atrophy, but it has been replaced by the newer anti-tTG test. In a perfect world, anti-tTG and anti-endomysial will be in alignment, but in the real world sometimes one is positive and other not. A thorough doctor will run both. Reticulin antibodies have fallen out of favor
even longer ago, but I do know of one person diagnosed with biopsy
proven celiac disease who had only an isolated positive anti-reticulin
antibody.

What
do the antibody tests mean?

Having a
positive anti-tTG or anti-endomysial result means there is a very high
probability (90-95%) that villous atrophy will be found on biopsy.
However, a negative anti-tTG result does not absolutely rule out celiac
disease~ it just makes it less likely.

Because a positive
anti-tTG is such a strong indicator of intestinal damage, the trend
seems to be moving away from using the gliadin antibody testing at all.

Isolated
gliadin antibodies are a weaker indicator that the intestinal damage
needed for a Celiac Disease diagnosis will be found. However, gliadin
antibodies can be very meaningful,
particularly for those who present with neurologic disease. There are
also many people who have gastrointestinal and other symptoms that
improve on a gluten free diet, whose only hint of a problem with
gluten were positive antigliadin antibodies.

Insist
they include the antigliadin IgA / IgG, especially if you have
neurologic or other non-intestinal symptoms.

”But antigliadin
antibodies lackspecificity”IgG anti-gliadin antibodies have beenthe best diagnostic marker in the neurologicalpopulation we have studied. IgGanti-gliadin antibodies have a very highsensitivity for CD but they are said tolack specificity. In the context of a rangeof mucosal abnormalities and the conceptof potential CD, they may be theonly available immunological marker forthe whole range of gluten sensitivity ofwhich CD is only a part. Further supportfor our contention comes from our HLAstudies. Within the group of patientswith neurological disease and glutensensitivity (defined by the presence ofanti-gliadin antibodies) we have found asimilar HLA association to that seen inpatients with CD: 70% of patients havethe HLA DQ2 (30% in the general population),9% have the HLA DQ8, and theremainder have HLA DQ1. The finding ofan additional HLA marker (DQ1) seen inthe remaining 20% of our patients mayrepresent an important difference betweenthe genetic susceptibility of patientswith neurological presentation tothose with gastrointestinal presentationwithin the range of gluten sensitivity.

”But antigliadin antibodies
havebeen
superseded byanti-endomysial andtransglutaminase antibodies”The introduction of more
CD specificserological markers such as
antiendomysiumand more recently
transglutaminaseantibodies may have helpedin diagnosing CD but their sensitivity asmarkers of other manifestations of glutensensitivity (where the bowel is notaffected) is low. This certainly reflectsour experience with patients with glutensensitivity who present with neurologicaldysfunction. Endomysium and transglutaminaseantibodies are only positivein the majority but not in all patientswho have an enteropathy. Patients withan enteropathy represent only a third ofpatients with neurological manifestationsand gluten sensitivity. Antigliadinantibodies unlike endomysium andtransglutaminase antibodies are not autoantibodies.They are antibodies againstthe protein responsible for gluten sensitivity.

SERONEGATIVE CELIAC DISEASE EXISTS

It is also possible to
have seronegative celiac disease. Some studies say this may occur in as
many as 20%. A negative result on all antibody tests does notcompletely
rule out celiac disease. If someone is highly symptomatic they should
pursue a biopsy even if all blood work is negative.

For a "gold standard" diagnosis,
yes..you need a biopsy. If a "gold standard" diagnosis is not important
to you, nobody can force you to have a biopsy if you don't want one.
Some people are happy to let their response to the diet speak for
itself. Others want to have a solid diagnosis before committing to
strict dietary changes for a lifetime. Most, but not all, doctors will
recommend a biopsy to confirm the diagnosis.

One thing is for sure, if you think you will ever want
to have a biopsy done...the time to do it is BEFORE you begin
experimenting with a gluten free diet. You must be consuming gluten for
the biopsy to be accurate.

A biopsy may be important
to rule out other co-existing conditions which might be contributing to
your symptoms. However, if symptoms do not improve with dietary changes,
a biopsy could always be performed at a later date.

Some doctors
who take a common sense approach will diagnosis celiac disease based
upon positive blood work and/or symptoms which improve on a gluten free
diet alone. A positive anti-tTG, for example, is a very strong indicator
that damage will be found on biopsy. So strong, in fact, that some
doctors are beginning to question the necessity of performing the
invasive procedure.

Whether
or not you need biopsy proof of celiac disease is a personal decision
to be made by you and your doctor. There are many pro's and con's to be
considered, and a case can be built in either direction.

Among 11 relatives, at the time of the first screening, 6 already had a positive serology and histology for CD, while 5 became positive only after a period of 2 to 5 y of negative testing. Conclusion: CD can manifest itself after years of negative serological testing. Onset of coeliac disease: a prospective longitudinal study. PMID: 14632329 Oct 2003

Also: Follow-Up to the Catassi Study -- Scandinavia Colin, et al, published a follow-up study to the Catassi (Coeliac Disease in the Year 2000:Exploring the Iceberg - University of Ancona, Italy) in the Scandinavian Journal of Gastroenterology 28(7):595-8, 1993, which demonstrated that approximately one third of the patients from the Catassi Study who had raised antibodies but no villous atrophy, did have villous atrophy when tested two years later. These results raise the number of diagnosed celiacs from the Catassi, et al study to over 1 in 200.